Design of conductive shield for wireless power transfer system for electric vehicle considering automotive body

In this paper, we quantitatively investigated the undesirable effects of the automotive body on the performance of and the magnetic field distribution around the wireless power transfer (WPT) system for electric vehicle (EV), and what is more, we found that the magnetically coupled coils of WPT system for EV can almost completely be shielded from the detrimental influences of the automotive body by employing the intermediate conductive shield only with the diameter which is at least 4 times larger than the air gap length. The simulation and measurement data show that, by employing the intermediate conductive shield, the spot value of the magnetic near field is reduced by at least 70 % and the power transfer efficiency as high as 96 % can be achieved under the automotive body.